In a mobile terminal communication system, a mobile terminal in the service area of the base station receives radio waves from the base station when it is turned on or it is reset, transmits a request to the base station that communication therebetween can be performed, and changes to a state in which it can communicate with the base station (link established state). Then, the mobile terminal notifies the base station of its unique information and performs an authentication and location registration process for registering the existence area of the mobile terminal to the network including the base station. Then, the mobile terminal performs a link open process and changes to an idle state. Then, when communication, such as call connection (the reception of a call) or call transmission from the base station, is needed, the mobile terminal changes to a communication state with the base station.
In the prior art, when a test device (which is also referred to as a pseudo-base station apparatus) tests the mobile terminal which communicates with the base station, message exchange is performed with the mobile terminal to be tested by the same process as that performed by the base station, as shown in the example of FIG. 4.
That is, at the beginning of the operation, a mobile terminal 1 transmits a message Mu1=rrc Connection Request (establishment Cause: registration) for requesting communication with the base station in order to register the location. A test device 10 transmits a message Md1=rrc Connection Setup for designating, for example, a channel used for communication with the mobile terminal 1, in response to the request. Hereinafter, Mu (number) is referred to as a message transmitted by the mobile terminal 1 and Md (number) is referred to as a message transmitted by the test device (pseudo-base station apparatus) 10.
When receiving the message, the mobile terminal 1 sets, for example, the channel used for communication on the basis of the designated information and transmits a message Mu2=rrc Connection Setup Complete which indicates the completion of the setting. Then, the mobile terminal 1 transmits a connection request message Mu3=initial Direct Transfer (Attach request) for location registration.
The process from Mu1 to Mu2 is a link establishment process and Mu3 is a connection request process. However, here, it is assumed that a link is established when the process from Mu1 to Mu3 is performed. After the establishment of the link is completed, the test device proceeds to an authentication process for the mobile terminal 1.
That is, the test device 10 transmits a message Md2=downlink Direct Transfer (Authentication and ciphering request) indicating the value of a random number (RAND) which is used in the authentication calculation of the mobile terminal 1. When receiving the message, the mobile terminal 1 performs a predetermined operation using the RAND value and its own information, inserts the calculation result into a message Mu4=uplink Direct Transfer (Authentication and ciphering response), and returns the message.
The test device 10 determines whether the calculation result is correct. When it is determined that the calculation result is correct, the test device 10 transmits a message authentication use start notification message Md3=security Mode Command. The mobile terminal returns a message Mu5=security Mode Complete which indicates the reception of the message.
Then, the test device 10 transmits a message Md4=downlink Direct Transfer (Identity request: IMSI) for inquiring about a user identification number IMSI (International Mobile Subscriber Identity) which is allocated to each user of the mobile terminal. The mobile terminal 1 returns a response message Mu6=uplink Direct Transfer (Identity response). In addition, the IMSI and key information (Authentication key) unique to the user which is used for authentication are stored in a SIM of the mobile terminal.
Then, the test device 10 transmits a message Md5=downlink Direct Transfer (Identity request: IMEI) for inquiring about a terminal identification number IMEI (International Mobile Equipment Identity) which is allocated to each mobile terminal. The mobile terminal 1 returns a response message Mu7=uplink Direct Transfer (Identity response).
Then, the test device 10 transmits a message Md6=downlink Direct Transfer (Attach accept) for accepting a location registration request (Attach request). The mobile terminal 1 returns a response message Mu8=uplink Direct Transfer (Attach Complete).
The authentication and location registration of the mobile terminal 1 are completed by these processes. The test device 10 transmits a message Md7=rrc Connection Release for designating the opening of the channel in order to open the link. The mobile terminal 1 outputs a response message Mug=rrc Connection Release Complete and then enters the idle state.
Then, the test device 10 transmits a connection request message Md8=paging Type 1 for a test to the mobile terminal 1 which is in the idle state. When receiving the message, the mobile terminal 1 returns a message Mu10=rrc Connection Request (establishment Cause: terminating Conversational Call) for requesting communication with the test device 10 again.
Then, the test device 10 transmits a message Md9=rrc Connection Setup for designating, for example, a channel used for communication with the mobile terminal 1.
When receiving the message, the mobile terminal 1 sets, for example, the channel used for communication on the basis of the designated information and transmits a message Mu11=rrc Connection Setup Complete which indicates the completion of the setting. Then, the mobile terminal 1 transmits a connection request message Mu12=initial Direct Transfer (paging response).
The exchange of the messages Md8 to Mu12 is a link re-establishment process for a test. After the link establishment is completed, the test device 10 transmits a message Md10=downlink Direct Transfer (Authentication and ciphering request) indicating a RAND value which is used for authentication calculation in order to authenticate the mobile terminal 1. When receiving the message, the mobile terminal 1 performs predetermined calculation using authentication key information (Authentication key) and the RAND value and returns a message Mu13=uplink Direct Transfer (Authentication and ciphering response) including the calculation result.
Then, the test device 10 determines whether the calculation result is correct. When it is determined that the calculation result is correct, the test device 10 transmits a message authentication use start notification message Md11=security Mode Command. When receiving the message, the mobile terminal 1 returns a message Mu14=security Mode Complete which indicates the reception of the message.
The mobile terminal 1 to be tested is authenticated by the exchange of the messages Md10 to Mu14. When the authentication ends, the test device 10 transmits a message Md12=downlink Direct Transfer (Activate RB Test Mode) for setting test mode connection to the mobile terminal 1. When receiving the message, the mobile terminal 1 returns a response message Mu15=uplink Direct Transfer (Activate RB Test Mode Complete).
Then, the test device 10 transmits a message Md13=radio Bearer Setup which designates, for example, the channel used for data communication for a test. When receiving the message, the mobile terminal 1 returns a message Mu16=radio Bearer Setup Complete which indicates the completion of the setting.
Then, the test device 10 transmits a message Md14=downlink Direct Transfer (Close UE Test Loop) for setting the type of the test mode to the mobile terminal 1. When receiving the message, the mobile terminal 1 returns a message Mu17=uplink Direct Transfer (Close UE Test Loop Complete).
After the mobile terminal 1 changes to the test mode in this way, the transmission and reception test is performed for the mobile terminal 1. Examples of the test include tests for the transmission functions of the mobile terminal 1, such as a transmission power test, an EVM test, and an ACLR test, and tests for the reception functions of the mobile terminal 1, such as a reception sensitivity test and a loop-back test.
As such, the test device according to the prior art changes the mobile terminal to the state in which the mobile terminal can be tested by the same process as the communication process between the base station and the mobile terminal and then tests the mobile terminal. In recent years, the processing speed and function of the mobile terminal have increased and a multi-band mobile terminal has been developed. As a result, the test time increases due to an increase in the number of test items. When the mobile terminals are tested one by one in a manufacturing line, there is a strong demand for a technique capable of effectively performing the test.
As one of the test methods, the following Patent Document 1 discloses a technique which stores information required for location registration in a mobile terminal in advance, omits a location registration process between a test device and the mobile terminal, and tests the mobile terminal in an idle state.